The game doesn't randomly decide this, not by any means. Complacency in your side doesnt randomly pop it, it builds up over time, and thus is genrerally avoidable.
I never said gung ho. But you are winning the ball high up the pitch, and pressing very high, that is a very aggressive approach, any mistake in your pressing allows for acres of space on the counter. You will restrict most sides to few shots, but the few they will get on the break will tend to be very good ones, as they have acres of space to attack behind your back line. That is the nature of a high pressing game. Everything is a trade off.
There is a reason why not that many teams play a a persistent pressing game, and why even fewer can do it for 90 minutes. And fewer still who can do it consistently over an entire season.
Your defenders are ranked 21st for marking, tackling and positioning (im hoping at the very least they are strong in anticipation pace and decison making?), and you are playing a high, heavy pressing game? Can you not see the inherent risk in that? The demands of that kind of play is exceptionally high, and you are doing it with defenders who arent particularly good enough, really you should be pleased that its' been this successful so far. You took tactics into consideration, but did you take your players? In terms of attributes both hidden and seen? If any of your players lack the ability to be consistent, it creates a weakness. Players who are not up to scratch ability wise create a weakness. Enough factors come together for any one match, and you can lose, and lose heavily
Given that as you say you are generally successful, but that your defenders are not actually up scratch, can you not see why a complacent display, or any kind of off day, inconsistent players, or sheer bad luck would see your side get utterly humped?
You play an approach that carries a relatively high amount of risk for your defenders. One that requires your players to be focused and consistent at all times, something that can be difficult in game and in real life. In your approach there is little room for failure in your defenders, you are asking from players who cant necessarily deliver all the time. Granted, much better defensive players for that kind of player will see less of this. But none of this is unexpected or particularly harsh.
I woulnt neccesarily change it, I'd absolutely accept there will be times that it will backfire, and occasionally spectacularly so. at least until i get a better defensive line.
In short: Buy better defenders.
